A photobase generator which generates a primary amine or a secondary amine (patent document 1 and non-patent document 1) is not suitable as a catalyst for a polymerization reaction or for a crosslinking reaction because of its low activity because the basicity of a primary amine or a secondary amine to be generated is low (i.e., pKa<8). Moreover, there was a problem that a large amount of photobase generator was needed in order to perform a sufficient reaction because these amines have active hydrogen atoms and therefore the amines themselves might react if they are used for polymerization reactions or crosslinking reactions of an epoxide or an isocyanate.
A photobase generator capable of generating a strong base (a tertiary amine, pKa of from 8 to 11) or a super-strong base (e.g., guanidine and amidine, pKa of from 11 to 13) has been proposed so that such a problem should be solved (patent documents 2 to 4 and non-patent document 2).
Moreover, there has been proposed a photobase generator which changes in chemical structure through a photoreaction to generate amidine only when receiving light (patent document 5).    Patent document 1: JP 10-7709 A    Patent document 2: JP 2005-107235 A    Patent document 3: JP 2005-264156 A (U.S. Pat. No. 7,300,747 B2)    Patent document 4: JP 2007-119766 A    Patent document 5: JP 2005-511536 T (WO 03/033500 A1)    Non-patent document 1: Dictionary of Optical Application Technologies and Materials, published by Sangyo-Gijutsu Service Center Co., Ltd., 2006, p. 130    Non-patent document 2: J. Photopolym. Sci. Tech., Vol. 19., No. 1 (81) 2006